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Biomedical subjects

L G Jackson

Publications and source records attributed to L G Jackson.

At least 55 records · Page 3Linked to original sources
PubMed1986

Two abnormalities of hexosaminidase A in clinically normal individuals.

Two abnormalities of beta-hexosaminidase A (HEX A) activity are described. One, found in two unrelated Jewish children, was characterized by the complete absence of HEX A activity in serum, but low levels of activity in leukocytes and fibroblasts using artificial substrate. The other, found in a non-Jewish man, was characterized by uniformly low levels of HEX A activity in leukocytes, fibroblasts, and serum against artificial substrate. In all cases, the pH optimum of HEX A was normal, there was no increased lability at 37 degrees C, and no inhibitor was detected to account for the deficiency of activity. Cultured fibroblasts of these individuals were capable of synthesizing and processing alpha- and beta-subunits of HEX A and capable of cleaving GM2 ganglioside. The patients, ranging in age from 6 to 30 years, are clinically normal. They are probably genetic compounds carrying the classical Tay-Sachs gene and a differently mutated allele that imparts the anomalous phenotypic features observed.

Adult↗
PubMed1986

Suspected genetic disease.

To formulate an accurate diagnosis and provide adequate management of genetic problems associated with ear malformations or hearing loss, the otolaryngologist must have an awareness of possible genetic causes of these disorders. Careful evaluation of the family history as well as examination or testing of family members might be required to arrive at a correct diagnosis. The clinical geneticist can provide assistance to the clinician with contemporary information about additional useful diagnostic studies, the possibility of prenatal diagnosis of the disorder, or in the process of genetic counseling so as to enhance the family's overall adjustment to the problem.

Abnormalities, Multiple↗
PubMed1985

X-linked motor-sensory neuropathy type-II with deafness and mental retardation: a new disorder.

We report on a family with an apparently X-linked neuromuscular disease. Electrophysiologic tests and electron microscopic studies are consistent with the diagnosis of hereditary motor sensory neuropathy type II (HMSN-II), one form of Charcot-Marie-Tooth disease. The manner of inheritance, the observation that males are severely affected from infancy, and the frequent association of deafness and/or mental retardation with the neuromuscular disorder are not usual for HMSN-II and suggest that this family may have a previously undescribed genetic disorder. The peripheral neuropathy did not appear to be linked to the Xg blood group. Minor abnormalities of sensory nerve conduction, electromyography, and hearing were separately identified in female relatives in this family, but were not consistent enough to be useful in the identification of carriers for this gene.

Adult↗
PubMed1985

Sixty-four patients with Brachmann-de Lange syndrome: a survey.

We surveyed 64 individuals with the diagnosis of Brachmann-de Lange syndrome (BDLS) to determine the natural course and cause of the disorder. The 64 individuals were ascertained through membership in a national organization, the Cornelia de Lange Syndrome (CDLS) Foundation, comprised of families who have a relative with BDLS. We surveyed 64 families by questionnaire and personally examined 24 of the 64. Our data suggest that lower birth weight correlates with a more severe phenotype, specifically including severe upper limb malformations and greater psychomotor retardation. The lower birth weight group showed a significant excess of females. The miscarriage rate was normal and there were no recurrences reported in the 64 families we surveyed. Major management problems included feeding problems and projectile vomiting, behavioral problems including frequent tantrums, hearing and dental difficulties, and recurrent respiratory tract infections. The oldest, teenaged subjects in our study entered puberty; although pregnancy has not been reported in the syndrome, it is likely that people with BDLS are fertile. Though most BDLS children reared at home survive through adolescence, a significant degree of psychomotor retardation and difficult medical management problems still occur.

Birth Weight↗
PubMed1984

Subclinical autoimmune disease and unexplained abortion.

Although it seems likely that some patients with unexplained repeated abortions have early or subclinical autoimmune disease, there are no reports on the incidence of autoimmune serologic abnormalities in such patients by use of a series of tests. This diagnosis would suggest a treatable etiology for reproductive loss. We performed 11 serologic autoimmune tests in sera from 14 patients with three or more unexplained abortions (group II) and compared these results to those of 16 control patients with an established diagnosis for repeated abortions (group I). The groups were similar in age, gravidity, number of spontaneous abortions and live births, and in the interval from last abortion to serum sampling. A positive antinuclear antibody test plus at least one other positive test was found in four of 14 (29%) patients in group II (p less than 0.05). The tests that identified all these patients included levels of antinuclear antibody, antibodies to DNA or extractable nuclear antigen, and low levels of complement 3.

Abortion, Habitual↗
PubMed1983

Repeated pregnancy loss.

Debate persists over the value of chromosome analysis of couples with repeated pregnancy loss. Therefore, we studied the records of all patients referred to the Genetics Division at Thomas Jefferson University for repeated pregnancy loss. Couples were divided into three groups according to the reason for evaluation. In group I (two consecutive abortions) significant chromosome abnormalities were found in 1.8% of individuals; in group II (three or more consecutive abortions) 2.3% of individuals had a chromosome abnormality; and in group III (50% fetal loss) 1.8% of persons had abnormal chromosomes. These rates are lower than those reported by others, but are still ten times higher than those expected in the general population and affirm the value of doing a chromosome study in such couples. In addition, we found increased incidence of liveborn offspring with congenital abnormalities in couples evaluated for the above indications, and found a high incidence of a family history of repeated suboptimal pregnancy outcome. The significance of these findings is discussed.

Abortion, Habitual↗
PubMed1983

Juvenile GM2 gangliosidosis (AMB variant): inability to activate hexosaminidase A by activator protein.

Two sibling from a consanguineous Puerto Rican marriage were found to have a juvenile-onset type of lipidosis first noted at age 2 1/2 by expressing difficulties with motor function and developmental delay. They continued to deteriorate, showing muscle atrophy, spasticity, and loss of speech, and death occurred at ages 7 and 8. Examination of the brains from these patients revealed that the concentration of GM2 ganglioside was about 56% of the total gangliosides. Hexosaminidase and percent hexosaminidase A (HEX A) and other lysosomal enzymes were normal in cultured skin fibroblasts, liver, and brain. The concentration of the activator protein required for the enzymatic hydrolysis of GM2 ganglioside was in high normal levels in the brain of the patient available. However, the HEX A from the patient's brain and liver as well as from skin fibroblast lysates could not be activated to hydrolyze GM2 ganglioside by the activator protein from a control or himself. The HEX A from a control could be activated by the activator protein from controls or this patient. These patients appear to have a defect in HEX A, which does not affect it heat stability, electrophoretic migration, and activity toward fluorogenic substrates, but may affect the binding of the activator protein required for GM2 ganglioside hydrolysis. We propose to call these patients the AMB variant of GM2 gangliosidosis to denote the mutation in HEX A but with normal levels of HEX A and B with synthetic substrates. This is to distinguish these patients from those missing the activator protein and normal HEX A and B levels.

Brain↗
PubMed1981

Ultrasonographic parameters in the prenatal diagnosis of Meckel syndrome.

The ability to make a prenatal diagnosis of Meckel syndrome (encephalocele, polydactyly, and polycystic kidney) by ultrasound is described. Three cases are detailed; in 2 of these the diagnosis was made at 18 and 36 weeks' gestation, respectively. In case 1 Meckel syndrome was identified by the presence of oligohydramnios, microcephaly, and enlarged cerebral ventricles. In case 2 oligohydramnios was associated with an encephalocele, bilateral renal enlargement, and a polydactyly. In case 3 the diagnosis was excluded in a fetus at risk. The usefulness of ultrasound in making this diagnosis is discussed for cases in which the amniotic fluid alpha-fetoprotein value is normal, inconclusive, or unobtainable.

Abnormalities, Multiple↗
PubMed1979

Prenatal diagnosis of Tay-Sachs disease: studies on the reliability of hexosaminidase levels in amniotic fluid.

Measurement of hexosaminidase A activity in amniotic fluid was found to be a reliable diagnostic test in the prenatal diagnosis of Tay-Sachs disease. Including normal control specimens, analysis of 39 amniotic fluid samples have correctly predicted the condition of the fetus or, in pregnancies not yet come to term, have been in agreement with results from cultured cell extracts. In each case where both fluid and cultured cell extracts were analyzed, the results were in agreement. Analysis were performed by means of Cellogel, starch gel electrophoresis, polyacrylamide gel electrophoresis, or heat inactivation.

Amniotic Fluid↗
PubMed1978

Autosomal dominant inheritance of annular pancreas.

This report describes a family with apparent autosomal dominant transmission of congenital annular pancreas. Four individuals in two generations were affected; all developed duodenal obstruction. The implications for genetic counseling are discussed.

Female↗